Steam Engine Correspondence/Ron Whaley
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Steam Engine Correspondence
July 15, 2011
On 7/15/2011 11:13 AM, Ronald Whaley wrote:
Mark,
I once worked at PKI and a with the professor from the Australian National University on a converted Lister diesel engine to a 1200 psi steam engine that we increased it’s capacity from 25 KW to 45KW at which point he determined that the addition of a 4th cylinder was needed to produce 50KW reliably. If would need so hands on information please feel free to drop me a note
Ron Whaley PS Engineering, Ltd
From: Mark Norton [1] Sent: Friday, July 15, 2011 12:21 PM To: Ronald Whaley Cc: Mark Norton; Marcin Jakubowski Subject: Re: PKI steam engine
Thank you for getting in touch with me, Ron. We tried to track down the details on the White Cliffs Solar Installation, but discovered that many of the critical details were left out of the final report [2], largely due to the transfer of intellectual proper to PKI. I am of the opinion that PKI was largely interested in the solar concentrators, but got the steam engine tech as well.
I don't know what the status of this information is. Does Power Kinetics still exist as a company? While I am sensitive about PKI's IP rights, I'm also interested in some of the (perhaps) less important details like:
- Valve dimensions and how much steam they let into a cylinder
- Timing such as steam cutoff
- What material the valves and bump pins were machined from
- How much of a vacuum was applied to the exhaust vents
I am leading a project as part of the Open Source Ecology initiative to develop and open source steam engine, in part based on the White Cliffs Steam Engine. The current design uses a bump valve control mechanism. You can see some of the design details at [3].
Any information you can provide to me would be greatly appreciated.
- Mark Norton
PS. Do you live in New York? I live just south of Ithaca.
On 7/15/2011 3:29 PM, Ronald Whaley wrote:
I was the one who came up with the final material selections for the ball valves and lift pins, the ones the professor Kaneff was using worked acceptably at 25KW, when we pushed the power output above that the outer surface of the balls would flake off and they would fall into the cylinder and cause real damage. The final ones where off the shelf items and held up to the max the steam engine could deliver just over 45KW. From my Navel Nuclear power background and many years on submarines I knew the chrome steel balls and steel lift pins needed to be replaced by 440C stainless steel balls, the lift pins and valve seats needed to be 316 stainless steel. This proved to be the combination I got professor Kaneff to employ during our testing in Troy. The diagrams in the paper you quote have no mention of the heat shield and lift pin locking plate employed on the top of the pistons, which where held in place by the lift pins. You can see all the parts along with the reduction in ball diameter and the damage that occurred from the balls falling into the cylinders in the pictures I found.
I hope all this is helpful to you.
Ron Whaley
July 18, 2011
From: Mark Norton [4] Sent: Monday, July 18, 2011 7:51 AM To: Ronald Whaley; Mark Norton; Marcin Jakubowski Subject: Re: PKI steam engine
The head shield was added to protect the face of the piston to protected it from the steam? Did the locking pin just hold the pins in place?
On 7/18/2011 9:10 AM, Ronald Whaley wrote:
The locking plate was there to keep the lift pins from vibrating loose like on an airplane engine, we bent the edge up against the flat on the lift pin that where threaded into the top of the piston. The stainless steal heat shield was there to protect the piston from the steam and to absorb the damage when the chrome ball valves flaked and fell into the cylinder. The modification to the 440 stainless steel balls solved the latter problem of the chrome flaking off exposing the plain steel to the corrosive environment of the 1200 psi oily steam.
Ron Whaley
From: Mark Norton [5] Sent: Monday, July 18, 2011 9:18 AM To: Ronald Whaley; Mark Norton; Marcin Jakubowski Subject: Re: PKI steam engine
Good to know about the heat shield and lock plate, thank you for that.
The current valve design calls for a machined part that looks like an arrow head in cross section. See http://opensourceecology.org/wiki/Steam_Engine_Build/Valve. While ball bearings can be purchased off-the-shelf, there might be some design advantages to the arrow shape:
- Bump pin impact is flat - less flaking
- Broader seal surface in valve seat - less steam leakage
What are your thoughts about this design verses the spherical ball bearing approach used in the White Cliffs engine?
- Mark
On 7/18/2011 9:32 AM, Ronald Whaley wrote:
I think you need to rethink the arrow design with the flat band contact if you are using high pressure steam. the lift pins had a concaved surface that mated with the balls. As I said the problem was one of corrosion and a hard surface with the standard chrome plated balls, the 440 stainless steel solved the corrosion issue and have no plating to flake off. The ball also gives a constantly changing surface contact band to eliminate the wire drawing leakage between the valve and the seat. Some things like this you can’t learn at school or from a book, but get from years of experience maintaining steam plants as I did in the navy before getting my degree.
Ron Whaley
From: Mark Norton [6] Sent: Monday, July 18, 2011 9:47 AM To: Ronald Whaley; Mark Norton; Marcin Jakubowski Subject: Re: PKI steam engine
What kind of spring did you use to keep the valve-ball in contact with the valve seat? Currently, we've spec'd an off-the-shelf IC valve spring with a seat load pressure of around 100 lbs. See http://opensourceecology.org/wiki/Steam_Engine_Specifications/Valve_Spring_Sources.
There was some concern raised early on that the heat of the steam would cause the springs to anneal and lose their compression ability over time. This caused the design to migrate towards having the springs separated from the steam chamber.
Regarding high pressure steam - I am not sure what pressures we will be operating under. First of all, the OSE steam engine will likely be driven from a variety of steam sources: mostly solar and solid fuel boilers (wood). Steam pressure many not be of the quality that the White Cliffs collector achieved. Secondly, there are safety considerations regarding high pressure/high temp steam. As an extension of this second point, high pressure steam devices are rigorously regulated in the US, often requiring regular inspections. Finally, it is likely that high pressures/high temps will lead to higher incidents of breakdown. Comments are welcome.
- Mark
On 7/18/2011 10:12 AM, Ronald Whaley wrote:
The spring was a light grade thin wire stainless steel, because of the vertical orientation of the cylinder I even had the engine running the one time I forgot to install the springs. The power output was not as high so I quickly shut it down and installed the springs then resumed the testing. The engine was almost idiot proof as was the plan.
PKI also ran into the boiler inspection issue in their design. The steam pressure tested at was 1200 psi super heated with the three cylinder version to get 45 KW that is why PKI shows 5 cylinder version. I left the company just after the boiler inspector refused to approver there design, I kept telling them that it was wrong to use thin walled tubing in it, just because it was used in the old Stanly Steamer boiler used in testing. I kept insisting that we needed to use sch 120 stainless pipe in the boiler at the test pressure as was my experience with navy boilers. One of the many reasons I left and started on my ME degree at Penn State vice getting it at RPI.
Ron Whaley
From: Mark Norton [7] Sent: Monday, July 18, 2011 10:49 AM To: Ronald Whaley; Mark Norton; Marcin Jakubowski Subject: Re: PKI steam engine
So you never ran into problems with spring failure? That's interesting.
On a different note, our design is similar to yours in that steam is exhausted by the piston uncovering an exhaust hole near the end of the stroke. While I do believe that this is sufficient to fully exhaust the cylinder of spent steam, as the piston starts to move up again, the exhaust hole is closed. >From that point onwards, the piston is compressing air in cylinder, thus wasting work.
My understanding is that PKI engine relied on a vacuum on the exhaust vent (generated by the condenser) to avoid wasted compression work. Our current design doesn't have the benefit of a vacuum on the exhaust. How much will this impact performance of the engine? Is it a "show stopper" issue? How much of a vacuum was applied to the converted Lister Engine?
BTW, was the Lister Engine used in your Naval experience? Is that why it was selected?
- Mark Norton
On 7/18/2011 11:35 AM, Ronald Whaley wrote:
The exhaust port on the cylinder at end of the stroke is a very old concept, US subs used this long ago, they even had twin pistons in a common cylinder with a 5 degree offset in cranks to keep from locking up. This allowed them to put a blower on one crank to purge the exhaust and hence the snorkel mast for under water operation of the diesel for higher speeds. The Lister/GM diesel was the setup professor Kaneff had before bringing it to the US, I think it was more of a “Junk Yard Wars” type of thing, they where the parts he could find at the time based on his equations for cylinder number, stroke length and exhaust port on the bottom of the stroke.
The system efficiency will be lower as you know without connecting the exhaust to a condenser to draw a vacuum, we also had a small vacuum pump in the system to constantly purge the air from the system (I know not in the diagram, kind of like a surge tank with a few psi steam blanket). You need to ensure your system stays fee from air or you will be dealing with rust and sludge issues in the collector and boiler. Air contains oxygen as you know, this promotes rust and that will kill your system. The other thing you need to know about is boiler water chemistry even in very low pressure boilers, high temperatures and even the smallest amount of chlorine in the water leads to chloride stress corrosion.
I never had a spring failure nor did professor Kaneff even mention one to me. As I said the engine would run without them but there was a lower power output. We were trying to get the engine up to the capacity of the PKI collector that was rated at 50 KW by our testing at Sandi National Labs and make it reliable over 2000 hours (between rebuild inspections as scheduled).
I told you that you hit the jackpot of knowledge that the others had no clue of.
Ron Whaley
From: Mark Norton [8] Sent: Monday, July 18, 2011 1:21 PM To: Ronald Whaley; Mark Norton; Marcin Jakubowski Subject: Re: PKI steam engine
Were the valve seats conical or spherical to match the valves?
How much of a clearance did you use (the space between the cylinder end at piston face at top-dead-center)? Books on the subject drive one towards a small clearance, but calculations indicate a larger one might be better.
- Mark
Ron Whaley on 7/18/2011 3:29 PM
The seats where conical and the gap between the heat shield and the under side of the heat was smaller than the diameter of the valve ball as can be seen in one of the pictures I sent. There are three balls in the picture, you can see the smallest one that fell into the cylinder and the damage it caused to the heat shield using the scale and the known cylinder diameter you can get your answer.
Ron Whaley
July 19, 2011
Ron:
Marcin Jakubowski and I were wondering if it would be possible to schedule a conference call with you some time this week. Most afternoons and evenings are open and we have a conference call line that we can use. When would be a good time for you?
- Mark Norton
